const fp = require('lodash/fp')

//数据
//horsepower 马力，dollar_value 价格 ，in_stock 库存
const cars = [
    {name:'Ferrair FF',horsepower:660,dollar_value:700000,in_stock:true},
    {name:'Spyker C12 Zagato',horsepower:650,dollar_value:648000,in_stock:false},
    {name:'Jafuar XKR-S',horsepower:550,dollar_value:132000,in_stock:false},
    {name:'Audi R8',horsepower:525,dollar_value:114200,in_stock:false},
    {name:'Aston Martin One-77',horsepower:750,dollar_value:1850000,in_stock:true},
    {name:'Pagani Huayra',horsepower:700,dollar_value:1300000,in_stock:false}
]

let isLaskInStock = function (cars){
    let last_car = fp.last(cars)
    return fp.prop('in_stock',last_car)
}

// console.log(isLaskInStock(cars))

// function log(car){
//     return fp.prop('in_stock',last_car)
// }
let fr = fp.flowRight(fp.prop('in_stock'),fp.last)
console.log(fr(cars))

//使用函数组合fp.flowRight()、fp.prop()和fp.first()获取第一个car的name
fr = fp.flowRight(fp.prop('name'),fp.first)
console.log(fr(cars))

//
let  _average = function (xs){
    return fp.reduce(fp.add,0,xs) / xs.length
}

let averageDollarValue = function(cars){
    let arr = fp.flowRight(_average,fp.map(car=>car.dollar_value))
    return arr(cars)
}
console.log(averageDollarValue(cars))

